Lowering the A1c cutoff for prediabetes leads to less cost-effective preventive interventions, concluded CDC researchers.
Three major medical organizations have three different recommendations for prediabetes: the American Diabetes Association sets is at 6%, the International Expert Committee sets it at 5.7%, and the Expert Committee on the Diagnosis and Classifıcation of Diabetes Mellitus sets it at 5.5%.
So, who's right? The Centers for Disease Control and Prevention study looked at the issue from a cost-effectiveness standpoint, and determined that, assuming a conventional $50,000/QALY cost-effectiveness benchmark, the A1c cutoffs of 5.7% and higher were best. (Learn how to handle prediabetes from a clinical standpoint in ACP Internist's article on the subject.)
The CDC researchers created a Markov simulation to examine the cost effectiveness associated with a progressive 0.1% decrease in the A1c cutoff from 6.4% to 5.5% using the data of nondiabetic American adults from the National Health and Nutritional Examination Survey (1999-2006).
The study looked at two different interventions: a high-cost, resource-intensive approach that cost on average almost $1,000 per year, and a low-cost intervention with an annual cost of $300 per year. Researchers measured the cost per each quality-adjusted life year (QALY) at each A1c cutoff for both interventions.
Results appeared in the American Journal of Preventive Medicine.
Cutoffs of 5.7% and above were cost-effective, based on the conventional $50,000/QALY cost-effectiveness benchmark. The optimal cutoff may be lower if the cost of preventive interventions could be lowered without compromising effectiveness.
Lowering the A1c cutoff would increase the health benefıts of the preventive interventions at higher costs. The high-cost approach lowered the A1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $27,000 and $34,000 per QALY gained, respectively. Continuing to decrease the cutoff from 5.8% to 5.7%, from 5.7% to 5.6%, and from 5.6% to 5.5% would cost $45,000, $58,000, and $96,000 per QALY gained, respectively.
For the low-cost intervention, the A1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $24,000 and $27,000 per QALY gained, respectively. Continuing to lower the cutoff from 5.8% to 5.7%, 5.7% to 5.6%, and 5.6% to 5.5% would cost $34,000, $43,000 and $70,000 per QALY gained, respectively.